BRINGING vintage cars to the parks, estates and golf course fairways where they can flaunt their beauty and compete for honors in the summer’s many concours d’élégance events is a well-rehearsed process.

But as museums have assembled more exhibitions that showcase the artistry and historical significance of automobiles, the task of putting vehicles into public spaces — often in the center of a busy city — has become infinitely more complex. Cars, especially prewar classics, can be huge. And while museums are accustomed to dealing with large artworks, the vehicles present challenges on another scale entirely.

Placing 16 cars inside the Portland Art Museum for the “Allure of the Automobile” exhibition, which opens this weekend, has been the job of Donald Urquhart, director of collections management for the museum.

“These cars present problems, not the least of which is getting into the building,” he said. “Our doors aren’t as big as some of these cars.”

Mr. Urquhart is the man responsible for the logistics of maneuvering the rare, important and valuable cars into the museum’s galleries for the exhibition.

Displaying cars as art took a big step forward in popularity in 1951 with the “Eight Automobiles” exhibition at the Museum of Modern Art in New York City. More recently, cars from the collection of the clothing designer Ralph Lauren were displayed at the Museum of Fine Arts in Boston in 2005 and at the Louvre in Paris this spring.

The “Allure of the Automobile” opened at the High Museum of Art in Atlanta in 2010. With a few changes, the same exhibition has come to Portland.

It was not easy to persuade the owners to lend their cars to a museum at all — let alone twice. When Brian Ferriso, executive director of the Portland Art Museum, approached the High Museum about bringing the show across the country, he was told that getting the cars had been difficult.

But because Mr. Ferriso was approaching the exhibition as a study in industrial design, most of the lenders agreed to a second stint.

“I think they look at these objects as works of art rather than merely technological wonders,” he said of the owners. “Car museums contextualize the automobiles to the degree that they’re very much in the pantheon of auto history. Now we’re putting these in the history of 20th-century industrial design.”

The lenders also see the cars as art to be driven. “Working with lenders is different than borrowing a painting or sculpture from somebody,” Mr. Urquhart said. “The lenders have different relationships with cars they drive. One lender said, ‘I can see this as art in an art museum for 90 days, but as soon as you give it back, I’m driving that car.’ ”

One car that appeared in Atlanta was withdrawn, the Dodge Firearrow III concept car. The guest curator, Ken Gross, formerly director of the Petersen Automotive Museum in Los Angeles, was able to procure a 1954 Plymouth Explorer design study, sister to the Firearrow, from the Petersen in time for the show’s setup days last week.

Mr. Urquhart said he welcomed the challenge of bringing in the cars.

“In every exhibition, you start with an e-mail picture,” he said. “Then you walk around carrying this 6-inch scale model. When I saw the Sting Ray the first time, I knew it was a 15-foot car, but it looked like it was 30 feet long.”

Mr. Urquhart and his team at the museum created scale models of the three galleries that would house the cars for the summer and a digital fly-through for a sense of the space. Model cars and scale photos pasted to foam backing were placed in the architectural model to visualize the exhibition, arrange it thematically and to make sure the cars would fit in the galleries.

Let’s follow the 1961 Ferrari 250 GT racecar, a class winner at the 24 Hours of Le Mans, into the museum as an example. When it arrived last Monday morning, it was driven onto a lift at the rear of the semi truck it shared with five other cars in the show. The lift was lowered to street level, where a section of parking spaces had been rented from the city by the museum for the nine delivery trucks that would be dropping off the show’s cars for two days.

Webb Farrer, who has been ushering rare and priceless cars to exhibitions for 30 years, hopped in, started the engine and drove the car up two plywood ramps, over the sidewalk, past the museum cafe, through the sculpture garden and to the entrance, where the doors and jamb had been removed.

The silver Ferrari was pushed into the building, past the ticket counter and through the interior doors to the first gallery, where it would be positioned just behind the ’61 Aston Martin DB4GT Zagato. Here, the wheels were raised onto special rolling dollies so it could be moved — as if it were on skates — to line up with blue tape on the platform in front of it. The dollies were removed and the car was pushed slowly onto the platform.

Mr. Farrer cited the two biggest, heaviest cars in the show — a 1937 Hispano-Suiza and a 1933 Pierce-Arrow — as the hardest to maneuver into place. The Hispano-Suiza had to be slid onto its platform sideways because there wasn’t room to line it up and roll it on.

The Hispano-Suiza was so wide it nearly scraped a metal artwork in the sculpture garden. The blue-gloved guide who was near the right fender had part of his hand pinched between car and art, luckily with little injury to himself and none to either object.

“Did we scratch the statue?” Mr. Farrer joked.

Once the cars were in place, the museum had a new aspect of curation to consider: car maintenance. The batteries, gasoline and oil must be tended to, and the museum had to be respectful of the city’s fire code.

And there are the little things to remember, like which car has a small, slow leak in the tire that will need to be reinflated all summer. Some of the cars leak fluids when left to sit for months.

Each car also comes with its own care and feeding instructions, per the lender’s preferences.

“When you rent a car, it comes with a photograph, and you mark the checks and the dents,” Mr. Urquhart said. “These come with four-page condition reports and photographs and instructions on handling and instructions on maintenance. One lender will say, ‘just knock the dust off with a towel,’ and the other will send a box of towels with a page of instructions on exactly how to dust.”

What makes “Allure of the Automobile” a treat for those who see it is the opportunity to see such a wide variety of important cars in one place, rather than having to travel all over the world to many museums and collections.